Self-checkout, point-of-transaction system including removable, electro-optically coded surveillance tags

ABSTRACT

A self-check apparatus is provided for processing a sales transaction of an article having an attached surveillance tag, each attached surveillance tag bearing a coded indicia such as a bar code. The self-checkout apparatus stores an indication of the articles which have been selected for purchase. When the surveillance tag is presented to the apparatus for deactivation, the bar code on the tag is scanned, and a check is made to verify that the surveillance tag is attached to an article which has been selected for purchase, and provided such verification is made, the surveillance tag is deactivated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of a U.S. patent application Ser. No.07/919,410, filed Jul. 27, 1992, now U.S. Pat. No. 5,594,228 which inturn is a continuation-in-part of U.S. patent application Ser. No.728,575, filed Jul. 11, 1991, which, in turn, is a continuation of U.S.patent application Ser. No. 414,450, filed Sep. 29, 1989, which, inturn, is a continuation-in-part of U.S. patent application Ser. No.236,249, filed Aug. 25, 1988, all said applications being assigned toSymbol Technologies, Inc., all of which have been abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This present invention generally relates to laser scanning systems forreading data in the form of indicia such as bar code symbols on articlesand, more particularly, to reading such indicia on surveillance tagsremovably mounted on the articles.

2. Description of the Prior Art

Various types of scanning systems are known in the prior art that areable to read bar code symbols. Bar code symbols are applied to thesurface of an article in order to represent data which can be read by ascanner. The data may be used to identify the article or othercharacteristics thereof. The bar code symbol itself is a coded patternof indicia comprised of a series of bars of various widths, spaced apartfrom one another to bound spaces of various widths.

Various types of desk-top or portable, hand-held scanner systems areexemplified by U.S. Pat. Nos. 4,369,361; 4,387,297; and 4,409,470--allof such patents being owned by the assignee of the instant invention andbeing incorporated by reference herein. Such scanners have generallybeen designed to operate at a certain working or reading distance fromthe symbol at a handheld or stationary position.

Typically, a scanner includes a light source such as a laser orsemiconductor device that generates a light beam. The use ofsemiconductor devices as the light source in scanner systems isespecially desirable because of their small size, low cost and low powerrequirements. The light beam is optically modified, typically by a lens,to form a beam spot of a certain size. It is preferred that the beamspot size be approximately the same as the minimum width between regionsof different light reflectivity, i.e., the bars and spaces of thesymbol. The relative size of the bars and spaces is determined by thetype of coding used, as is the actual size of the bars and spaces. Thenumber of characters per inch represented by the bar code symbol isreferred to as the density of the symbol.

The light beam is directed by optical components along a light pathtoward a target that includes a bar code symbol on the surface. Ascanning component is also disposed in the light path. The scanningcomponent may either sweep the beam spot across the symbol and trace ascan line across and past the symbol, or scan the field of view of thescanner or do both. A scanner also includes a sensor or photodetector.The photodetector has a field of view which extends across and slightlypast the symbol and functions to detect light of variable intensityreflected off the symbol. The photodetector generates electrical signalsrepresentative of the sequences of bars and spaces in the symbol. Theelectrical signals are then decoded into data descriptive of the symbol.

Various types of electronic article surveillance systems are also knownin the prior art. Such systems are used to prevent shoplifting andsimilar unauthorized removal of articles from a controlled area. Moreparticularly, such systems provide a specially designed tag or labelwhich is attached to the article. The tag or label contains active orpassive electronic circuitry or a magnetic media which is responsive ina certain manner to an external electromagnetic field. When the articlecontaining an activated tag or label is passed through a controlledexit, an alarm will be set off. In order to authorize the removal of thearticle from the control area, the tag or label must be either removedor deactivated by an authorized person. The present invention relatesmore particularly to surveillance systems that require deactivating ofthe tag, and to apparatus for deactivating a surveillance tag forauthorized removal of the article from the controlled area.

In one surveillance system known in the prior art, sensor-emitter labelsor tags contain a semiconductor diode and are applied to articles forthe purpose of surveillance. For deactivating such tags, various devicesare known in the prior art including, among others, radio frequencygenerators for burning out the diode. However, such generators aregenerally high powered and are coupled inductively to the tags by way ofan R.F. field.

Another surveillance system involves the use of tags containing ferritematerial that can be magnetized or demagnetized by a suitable magneticfield which alters the operating characteristic of the tag, therebydeactivating the same.

There are various devices known in the prior art for deactivation of asurveillance tag. U.S. Pat. No. 4,318,090 discloses a hand-held probehaving spaced contacts that are arranged to be applied to and drawnalong the surface of a surveillance tag that contains a diode. When theprobe contacts engage exposed terminals of the diode, a high current ispassed through the diode sufficient to destroy its conductingcharacteristics and thereby deactivate the tag.

There are a few systems in the prior art which combine both bar codereading and deactivation of surveillance tags. U.S. Pat. No. 4,141,078discloses an automated library circulation control system for processinglibrary books. The system includes at least one terminal having anoptical reader for book identification, and an electromagnetic activatorat each terminal for magnetizing and demagnetizing a magnetic strip ineach book.

In operation, a book is placed in a book tray at each terminal, and abar coded label on each book is read by an overhead optical scanner. Thebook is oriented in the book tray at the terminal with the label facingup and the spine of the book facing the front. The scanner reads a ninedigit number on the label and generates signals representing the barcode which are thereupon transferred to a computer.

The electromagnetic activator is operable at about the same time (col.1, lines 58 and 59) to activate or deactivate the magnetic strip in thebook. The activator is located under the book tray and is operative oncommand from the computer. Failure of a user to deactivate the stripbefore taking the book from the library will activate an alarm at thelibrary exit.

In all known prior art proposals, no light-reflective, coded indicia areassociated with the surveillance tag itself. Either there is noconfirmation of the tag removal for the system, or such confirmationmust depend on less reliable, user-dependent procedures.

Further, there are no know prior art proposals in which a surveillancetag having a coded indicia is associated with specific articles, andwhere the removal of the tag is enabled only where the specific articlehas been purchased or has been irrevocably selected for purchase.

Still further, there are no know prior art proposals where the codedindicia is displayed on a liquid crystal display, and where the codeindicia is dynamically changeable.

SUMMARY OF THE INVENTION

1. Objects of the Invention

It is an object of the invention to provide a device for reading barcode symbols which deactivates a surveillance tag under user controlafter it has been determined that the bar code symbol has beensuccessfully read.

It is another object of the invention to provide a two position triggeron a hand-held laser scanner in which one position initiates scanningand a second position deactivates a surveillance tag.

Another object of the invention is to associate coded indicia with thetag itself, thereby enabling tag removal to be automatically confirmed.

It is yet another object of the present invention to associate codedindicia with the surveillance tag itself, where the indicia of the tagis scanned, and based on the scanned indicia, if it is determined thatthe tag corresponds to an article which has been purchased, the removalof the tag is enabled.

2. Features of the Invention

Briefly, and in general terms, the present invention provides anapparatus for detecting indicia having portions of different lightreflectivity such as a bar code symbol on a label, and for deactivatinga surveillance tag associated with the label. More particularly, theapparatus includes a switch to initiate scanning a label containing abar code symbol. A sensor is provided having a field of view andoperative for detecting at least a portion of light of variableintensity reflected off the label and for generating an electricalsignal indicative of the detected light intensity. The apparatus furtherincludes a processor for processing the electrical signal to determinewhether the reflected light of variable intensity is indicative of thepresence of a bar code symbol. An enabling signal may be generated if asymbol has been detected. The apparatus also includes a second switch orswitch position for transmitting a deactivating signal to the target sothat a physical characteristic of the tag is changed so as to deactivatethe tag.

Another aspect of the present invention is to provide a method fordetecting indicia having portions of different light reflectivity suchas a bar code symbol on a label on a target, and for deactivating asurveillance tag associated with the target, including the steps ofmanually initiating scanning a label containing a bar code symbol anddetecting at least a portion of light of variable intensity reflectedoff the label with a sensor. An electrical signal is generated which isindicative of the detected light intensity. The electrical signal is todetermine whether the reflected light of variable intensity isindicative of the presence of a bar code symbol. A deactivation signalmay be manually initiated and transmitted to the target so that aphysical characteristic of the tag is changed so that the tag isdeactivated.

Still another aspect of this invention is to provide a system for, and amethod of, processing articles bearing coded indicia identifying thearticles in a self-checkout terminal at which surveillance tags arepresented. The tags are removably mounted on the articles. Each tagbears light-reflective, coded data identifying a respective article.

An electro-optical reader at the terminal reads the indicia to identitythe article to the terminal. Thereupon, the tag is removed by adecoupler or tag removal device at the terminal. In response to suchremoval, the reader reads the coded data on the removed tag. Theterminal now automatically knows that the tag associated with thearticle has been removed.

The indicia and data are advantageously UPC symbols, and may be the sameor different and, preferably, are sequentially numbered.

A still further aspect of this invention is to provide a system for, andmethod of, reading indicia to identify articles to be purchased,processing the purchase, and then, permitting removal of only thosesecurity tags which are attached to purchased articles.

An electro-optical reader at the terminal reads indicia to identify thearticle to be purchased. After the purchase is completed, theelectro-optical reader reads the indicia on a surveillance tag presentedfor tag removal, and a determination is made as to whether thesurveillance tag corresponds to an article which has been purchased. Ifit is determined that the tag is attached to an article which has beenpurchased, the terminal permits the decoupling or removal of the tag,and therefore, the article can be removed from the store.

A still further aspect of this invention is to provide a system for, andmethod of, reading indicia to identify articles to be purchased,processing the purchase, and then, permitting deactivation of only thosesecurity tags which are attached to purchased articles.

An electro-optical reader at the terminal reads indicia to identify thearticle to be purchased. After the purchase is completed, theelectro-optical reader reads the indicia on a surveillance tag presentedfor tag deactivation, and a determination is made as to whether thesurveillance tag corresponds to an article which has been purchased. Ifit is determined that the tag is attached to an article which has beenpurchased, the terminal permits the deactivating of the tag, andtherefore, the article can be removed from the store.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view of a gun-shaped, narrow-bodied,embodiment of a laser-based portable scanning and deactivation apparatusin accordance with the present invention;

FIG. 2 is a partially broken-away, top sectional view of the embodimentof FIG. 1;

FIG. 3 is a rear sectional view as taken along line 3--3 of FIG. 1;

FIG. 4 is a front elevational view of the embodiment of FIG. 1;

FIG. 5 is a front perspective view of the FIG. 1 embodiment, on asmaller scale, that diagrammatically shows the interconnection of thehead to the remainder of the scanning system;

FIG. 6 is a highly simplified perspective view of a point-of-sale systemincorporating another embodiment of the present invention;

FIG. 7A is a perspective view of another point-of-transaction systemaccording to still another embodiment of the present invention whichutilizes removable surveillance tags;

FIG. 8A is a side view of the system of FIG. 7A in block, diagrammaticform;

FIG. 9A is a flow chart depicting an embodiment of the operation of theFIG. 7A system;

FIG. 10A is a flow chart depicting a further embodiment of the operationof the FIG. 7A system;

FIG. 11A is a flow chart depicting a still further embodiment of theoperation of the FIG. 7A system; and

FIG. 12A is a flow chart depicting yet a further embodiment of theoperation of the FIG. 7A system.

FIG. 7b is a perspective view of another point-of-transaction systemaccording to still another embodiment of the present invention whichutilizes deactivatable surveillance tags;

FIG. 8b is a side view of the system of FIG. 7b in block, diagrammaticform;

FIG. 9b is a flow chart depicting an embodiment of the operation of theFIG. 7b system;

FIG. 10b is a flow chart depicting a further embodiment of the operationof the FIG. 7b system;

FIG. 11b is a flow chart depicting a still further embodiment of theoperation of the FIG. 7b system;

FIG. 12b is a flow chart depicting yet a further embodiment of theoperation of the FIG. 7b system.

FIG. 13 is a block diagram of a surveillance tag having a dynamicallychangeable display for displaying coded indicia according to stillanother embodiment of the present invention.

FIG. 14 is a block diagram illustrating a gas meter having a dynamicallychangeable display for displaying coded indicia according to stillanother embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1-5 of the drawing, reference numeral 10generally identifies a light-weight, narrow-bodied, streamlined,narrow-snouted, hand-held, fully portable, easy-to-manipulate,non-arm-and-wrist-fatiguing, laser scanning head supportable entirely bya user for use in a laser scanning system operative for reading,scanning and/or analyzing bar code symbols throughout the readingthereof, and further including deactivation apparatus for changing thestate of a surveillance device associated with a tag or label on whichthe bar code symbol is provided.

Bar code symbols comprise a series of lines and spaces of varyingwidths, forming a pattern that decodes to a multiple characterrepresenting a number, letter or graphic symbol which defines acharacteristic of the product or article bearing the symbol. Typicalsymbol bar codes in current use are the Universal Product Code (UPC),EAN Codabar and Code 39.

Turning now to FIG. 1, the head 10 includes a generally gun-shapedhousing having a handle portion 12 and an elongated narrow-bodied barrelor body portion 14.

The handle portion 12 has a cross-sectional dimension and overall sizesuch that it can conveniently fit in the palm of a user's hand. Both thebody and handle portions are constituted of a light-weight, resilientshock-resistant, self-supporting material, such as a synthetic plasticmaterial. The plastic housing is preferably injection molded, but can bevacuum formed or blow-molded to form a thin shell which is hollow andbounds an interior space whose volume measures less than about 50 cubicinches. This specific value is not intended to be self-limiting, but hasbeen provided merely to give an approximation of the overall maximumvolume and size of the head 10.

The body portion 14 is generally horizontally elongated along alongitudinal axis, and has a front region 16 at the front end, a raisedrear region IS at the rear end, and an intermediate body region 20extending between the front and rear regions. The body portion 14 has atop wall 11 above which the raised rear region 18 projects, a bottomwall 13 below the top wall, a pair of opposed side walls 15, 17 spacedtransversely apart of each other by a predetermined width-dimension, afront wall or nose 19, and a rear wall 21 spaced rearwardly of the frontwall.

A light source means, i.e. laser tube 22 having an anode or output end23 and a cathode or non-output end 25, is mounted within the bodyportion 14 lengthwise along the longitudinal axis, and operative forgenerating an incident collimated laser beam. In lieu of using a lasertube 22, a semiconductor laser may be used as the laser light source.The use of non-laser light, such as from a light emitting diode (LED) orincandescent source is also within the scope of the present invention.

An optic means, i.e. an optic train, is likewise mounted within the bodyportion, and is operative for directing the incident beam along a lightpath towards a reference plane located exteriorly of the housing in thevicinity of the front region 16, as shown in FIGS. 1 and 2. A bar codesymbol to be read is located in the vicinity of the reference plane,that is, anywhere within the depth of focus of the incident beam asdescribed below, and the light reflected from the symbol constitutes areflected laser beam which is directed along a light path away from thereference plane and back towards the housing. As best shown in FIG. 3,the optic train includes an optical bench 24, a negative lens which isfixedly mounted in a cylindrical bore of the optical bench 24, alight-reflecting mirror 26' which is fixedly mounted on an inclinedsurface of the bench, another light-reflecting 28 which is fixedlymounted on another inclined surface 29 of the bench, a positive orconvex lens 30 which is adjustably mounted on the bench by means of aset screw 31, and still another light-reflecting mirror 32 which isadjustably mounted on the bendable metal bracket 33. The bench 24 is aone-piece light-weight part machined or preferably molded by inexpensivemass-production techniques of a dimensionally stable, flame-retardantmaterial, such as Delrin™, or glass-filled Noryl™, preferably having ahigh dielectric breakdown (on the order of 500 volts/mil). In order totake into account the slight variations in beam alignment whichunavoidably result from different light sources and from tolerancevariations in the positioning of the light source itself, all elementsin the optical path are made large enough to allow the beam to passunobstructedly even if the beam is not exactly on center. This providesthe advantage that the bench can be inexpensively mass-produced withpractical tolerances.

Thus the beam emitted from the output end 23 first passes through thenegative lens 26 which functions to diverge the initially collimatedbeam. Then, the divergent beam impinges the mirror 26', and is thereuponreflected laterally to impinge the mirror 28, whereupon the beam isreflected upwardly to pass through the positive lens 30 which isoperative to converge the divergent beam to a generally circular spot ofapproximately an 8 mil to 10 mil diameter at the reference plane.

The converging beam from the lens 30 impinges on the adjustable mirror32, and is thereupon laterally reflected to a scanning mirror 44 whichforms part of the scanning means.

The scanning means is preferably a high-speed scanner motor 46 of thetype shown and described in U.S. Pat. No. 4,387,297, assigned to thesame assignee as the present application. The entire contents of saidpatent are incorporated herein by reference and made part of thisapplication. For purposes of this application, it is sufficient to pointout that the scanner motor 46 has an output shaft 41 on which a supportplate 43 is fixedly mounted. The scanning mirror 44 is fixedly mountedon the plate 43. The motor 46 is driven to reciprocally and repetitivelyoscillate the shaft in alternate circumferential directions over arclengths of any desired size, typically less then 360 degrees, and at arate of speed on the order of plurality of oscillations per second. In apreferred embodiment of this invention, the scanning mirror 44 and theshaft are jointly oscillated so that the scanning mirror repetitivelysweeps the beam impinging thereon through an angular distance A or anarc length of about 25 degrees and at a rate of about 40 oscillationsper second.

Stop means, i.e., an abutment 48, is fixedly mounted on a bracket 49which is, in turn, mounted on the bench 24. The abutment 48 is locatedin the path of oscillating movement of the plate 43 for the scanningmirror 44, for preventing the mirror from making a complete 360 degreerotation during shipping. The abutment never strikes the mirror duringscanning; the abutment serves to keep the mirror properly aligned, thatis, always facing towards the front of the head.

The scanning motor 46 is mounted on the bench 24 slightly offset fromthe longitudinal axis. Other miniature scanning elements can beutilized. For example, miniature polygons driven by motors can be used,or the various bimorph scanning oscillation elements described in U.S.Pat. No. 4,251,798 can be used, or the pentabimorph element described inU.S. Pat. No. 4,387,297 can be used, or the miniature polygon elementdescribed in U.S. Pat. No. 4,369,361 and assigned to the same assigneeas the present application, the entire contents of which are herebyincorporated herein by reference and made part of this disclosure, canbe used. Although only a single scanner element is shown in the drawingfor cyclically sweeping the laser beam across the symbol along apredetermined direction (X-axis scanning) lengthwise thereof, it will beunderstood that another scanner element may be mounted in the head forsweeping the symbol along a transverse direction (Y-axis scanning) whichis substantially orthogonal to the predetermined direction. In someapplications, multiple line scanning is preferred.

Referring again to FIGS. 1 and 2, the scanning mirror 44 is mounted onthe light path of the incident beam at the rear region 18 of the head,and the motor 46 is operative for cyclically sweeping the incident beamthrough an angular distance A over a field of view across the bar codesymbol located in the vicinity of the reference plane. A laserlight-transmissive scan window 50 is mounted on the raised rear region18, behind an opening 51 formed therein in close adjacent confrontingrelationship with the scanning mirror 44 thereat. As used throughout thespecification and claims herein, the term "close adjacent confronting"relationship between components is defined to mean that one component isproximally located relative to the other component, typically less thanone inch apart of each other. As shown in FIG. 1, the scan window 50 isconfigured and positioned in the light path of the incident beam topermit the latter coming from the scanning mirror 44 to travel adistance of less than one inch within the raised rear region 18, andthen to pass through the scan window 50, and thereupon to travelunobstructedly and exteriorly of and past the intermediate body region20 and the front region 16 of the housing, and then to impinge on thesymbol 103 located at or near the reference plane.

The closer the scanning mirror 44 is to the scan window 50, the largerwill be the field of view of the swept incident beam for a given scanangle. It will be noted that the width dimension of the scan windowrepresents a limiting factor of the sweep of the incident beam, becausethe housing walls bounding the scan window would clip and block any beamwhich was swept beyond the width of the scan window. Hence, as a rule,the scanning mirror is made as close as possible to the scan window tooptimize the field of view of the swept incident beam.

We turn next to the surveillance tag deactivator of the presentinvention. As we have noted above, various types of electronic article(EAS) surveillance systems are known. Such systems are used for avariety of applications, such as preventing shoplifting and similarunauthorized removal of articles from a controlled area. Moreparticularly, such systems provide a specially designed tag or labelwhich is attached to the article. The tag or label contains active orpassive electronic circuitry or a magnetic media which has at least twostates: an active state and a deactivated state. The tag is designed tobe responsive in a certain manner to the presence of an externalelectromagnetic field. The system is designed so that when the articlecontaining a tag or label in the activated state is passed through acontrolled exit, an alarm will be set off. If the tag or label isdeactivated, no alarm will be triggered, and the article may be removedfrom the control area. In order to authorize the removal of the articlefrom the control area, the tag or label must be either removed ordeactivated by an authorized person. The present invention relates tosurveillance systems that require deactivation of the tag, and moreparticularly to apparatus for deactivating a surveillance tag forauthorized removal from the area.

From a marketing standpoint, there are three basic technologies that maybe used in a disposable EAS tag: magnetic, intermediate RF, andmicrowave. The magnetic technique is believed the least reliable andworks to about three feet although such system are operable at 10 timeslower power than other configurations. The intermediate RF band isworkable to about six feet. The microwave technique is useful at thetwelve to fifteen foot range, suitable for the exits required for largedepartment stores.

In one surveillance system, sensor-emitter labels or tags contain asemiconductor diode and are applied to articles for the purpose ofsurveillance. For deactivating such tags, various devices are known inthe prior art including, among others, radio frequency generators forburning out the diode. However, such generators are generally highpowered and are coupled inductively to the tags by way of an R.F. field.

Another surveillance system involves the use of tags containing ferritematerial that can be magnetized or demagnetized by a suitable magneticfield. When the tag is moved into the magnetic field, the field altersthe operating characteristic of the tag, thereby deactivating it. Notethat a simple ferrite magnet is adequate to deactivate a magnetic tag byrebiasing a tag in its loop.

Another type article surveillance system is based on surface acousticwave technology. Such systems include a tag with a tiny chip made oflithium niobate, a remote interrogation unit and reader that includes aradio frequency transceiver, and a computer interface unit to performsignal processing, multiplexing and communications to a host computer.

Lithium niobate is extremely efficient in the conversion ofelectromagnetic energy (from the radio signal) into surface acousticwaves. A high resolution photolithographic masking process may be usedto create individual codes so that numerous individualized tags may bemanufactured. When the radio waves strike the tag, a phase modulatedsignal is sent back to the reader that carries the equivalent of abinary number of up to 28 bits or more.

The small, lightweight tag can be configured in many different ways,making it easy to attach or insert in a variety of objects. The tag isalso reusable, reliable and inexpensive. One of the main advantages of alithium niobate tag is that it can be read through any non-conductivesubstance such as wood, concrete and asphalt. Another superior featureis its reading range, which can be up to six feet.

The interrogation unit continually transmits a 915 MHz radio frequencysignal at a power of one to three milliwatts. This very low power signalis used to excite a lithium niobate crystal in the tag, which has nopower of its own, but does have a small antenna. The excitation of thecrystal creates a surface acoustic wave effect that alters the originalsignal in a manner unique for each tag. This new unique signal is echoedback and received by the reader, which passes it to the computerinterface. The computer interface decodes the signal, changes it fromanalog to digital, and sends it to the host computer.

Still another surveillance system utilizes a light sensitive element orswitch in the tag. The device transmitting a deactivating signalgenerates a laser light beam which functions to deactivate the tag orlabel by changing the state of a semiconductor component disposed in thelabel in the path of the light beam.

The laser light beam may be the same beam as the scanning beam. Thedevice on the tag may take a variety of different structures: it may bea switch, such as the Auston switch, or may be a transistor device, suchas a FET. The light beam may "blind" the FET so as to switch it intoanother state, representing a deactivated state.

Another embodiment of the tag is to utilize the latch up effect found inCMOS semiconductor devices. The latch up effect is normally considered adisadvantage of such devices and various circuit techniques have beenemployed in order to overcome such an effect. When a semiconductordevice is latched up it remains in a single state because of thepresence of charge carriers in a circuit element of the device. The sameeffect can be utilized to an advantage in an EAS tag allowing the laserbeam or external electric field to cause the semiconductor device tolatch up. Once the device is latched up, the EAS tag may be considereddeactivated and no subsequent exposure to additional laser light orexternal field will change the state back to an activated state.

Another embodiment of the surveillance tag according to the presentinvention is a laser-activated microwave semiconductor device. Thedevice consists essentially of back-to-back metal/thin oxide/silicon(MTOS) capacitors on a silicon chip.

Light from a laser (which may be a semiconductor laser) associated withthe scanner would be directed at the surveillance tag. The light wouldbe absorbed through the thinned areas of the aluminum electrodes of thecapacitors The aluminum is less than 10 nm thick in these areas. A layerof silicon dioxide about 10 nm thick under the electrodes provides alarge capacitance per unit area, and this capacitance is coupled to thecapacitance of the depletion layer in the silicon beneath the oxide. Theoxide is thick enough to be nonconducting at a voltage below 7 volts onone capacitor.

Operation of the device is based on the change in carrier-generationrate in the depletion layer caused by illuminating the MTOS capacitors.When illuminated by the laser, the depletion layer generates enoughcarriers to become conducting; the path between capacitor electrodesturns on very rapidly (equal to the product of the voltage and thedepletion layer capacitance). When the device is illuminated with alaser pulse, the capacitance increases to one-half the capacitance ofthe oxide layer, which is quite large. The charge increasesproportionately, creating a current pulse along a strip line on the chipsurface.

The capacitors can also be made to function as capacitively-coupledback-to back photodevices. In this mode of operation, the deviceresponds to low light levels with an estimated pulse response of 45 psfull width at half maximum.

The present invention is not limited to the use of any particular one ofthe EAS systems described, and the description that follows is intendedto be generic. The deactivating module 100 is shown in the head 10 inFIG. 1. When enabled, the deactivating module will transmit a signal tothe tag 101 which will change a physical characteristic of the tag sothat the tag is deactivated and the purchaser of the article 102 is ableto remove the article 102 from the controlled premises without settingoff an alarm. In the figure, an embodiment of the tag 101 is shown inwhich the bar code symbol 103 actually forms a part of the portion ofthe tag that is responsive to the transmitted signal, i.e. finger-likestructure representing an antenna or circuit in the tag. Furtherexamples of circuitry on the tag 101 will be described subsequently.

The operation of the optical scanning device in conjunction with adeactivation module in a retail application may be described as follows.The article to be purchased is presented to the checkout station withthe label 101 facing the scanner 10. The sales clerk positions thearticle 102 so that the scanner is able to read a bar code symbol 103 onthe label. The manually activatable trigger switch 76 is utilized in thepresent invention to selectively initiate scanning and/or to transmit adeactivating signal to the surveillance tag. There are several differentembodiments contemplated by the present invention:

In the first embodiment the switch 76 is a two position switch. Thefirst position corresponds to the function of initiating the scanningand the second position corresponds to the function of deactivating thesurveillance tag. The user has the option of scanning alone, ordeactivating the tag alone by pressing the switch to position number 1or position number 2 respectively. An alternate use of such a twoposition switch by a user would be to first initiate scanning, and afterit has been determined that a successful decode has taken place (by aaudible beep), the user can initiate deactivation by moving the switchto the second position. Successful deactivation may be indicated by anaudible beep of a different tone.

A second embodiment of the present invention consists of utilizing thetrigger switch to either initiate scanning or to initiate deactivation.Only upon successful completion of the selected function (i.e., by meansof a successful decode or an indication that deactivation has beensuccessful), will the scanner automatically execute the second function,that is, either deactivating or scanning. The signals representing thedata or information represented on the symbol is transferred to thecomputer 70 for accounting, inventory, and record-keeping purposes.

The deactivating module 100 is represented in FIG. 1 in highlydiagrammatic form as including a control circuit 105 and an antenna 106.In the embodiment shown in FIG. 1, it is assumed that the tag isdeactivated by generation of a radio frequency field, such as would begenerated by the antenna 106. The control circuit 105 is preferablycoupled to the signal processing means 55 which processes the analogsignal generated by the sensor means 54 to determine if a bar codesymbol has been detected. There are various approaches to enabling thedeactivating module, depending on whether or not a valid bar code signalhas been detected.

The signal processing means 55 may process the electrical signal todetermine whether the reflected light of variable intensity isindicative of the presence of a predetermined indicia pattern such as abar code symbol. The signal processing means 55 may further includemeans for generating an enable signal when the reflected light ofvariable intensity is indicative of the presence of predeterminedindicia pattern such as a bar code symbol. A deactivating signal will betransmitted to the label in response to the enable signal.

The deactivation of a surveillance tag may take any number of forms, anddepending on the type of tag, the deactivation signal changes somephysical aspect of the tag which deactivates it. U.S. Pat. No. 4,318,090is herein incorporated by reference to describe one embodiment of aspecific type of tag 101 and the technical procedure utilized inchanging a state of the tag. Of course, other types of tags and othersurveillance systems are also within the scope of the present invention.

For example, one simple surveillance system utilizes a tag containing amagnetic stripe. The magnetic stripe is demagnetized when the article ischarged or checked out. Deactivation of the stripe occurs on commandfrom the computer 70 after it is determined that the check-out has beenauthorized. Failure of the user to deactivate the stripe before takingthe article from the controlled area will initiate an alarm at the exit.More sophisticated surveillance systems will provide a unique code foreach article or class of articles so that the detection system willactually be able to identify the article. Such sophisticated systems mayalso include software which enables verification and confirmationmessages to be printed or displayed by an on-line printer or display toenable the checkout clerk to authorize the transaction. In specialapplications, such as a rental agency or library, the print out messagemay include the user's identification or credit card number, thedescription of the article or item rented, the date charged, and thedate due. If a reservation has been made the display will verify thereservation by user identification number, the article or item reservedand the date that the reservation or hole request was entered.

Our approach in the preferred embodiment of the present invention is toprocess the electric signal generated by the sensor means 54 todetermine whether the reflected light represents a bar code, a specificcategory or class of bar codes, or even a bar code with a specific code.A description of the signal processing means 55 will be presented indetail at a later point. If a bar code symbol is detected (or otherpredetermined criteria is satisfied), an enabling signal will begenerated by the signal processing means 55 and applied to the controlcircuit 105. The control circuit switches current into the antenna 106in response to the enabling signal, thereby generating a radio frequencyfield which, when placed sufficiently close to the tag 101, willdeactivate the tag 101.

Returning to the description of the scanning component of the presentinvention, as best shown in FIG. 2. The field of view of the sweptincident beam is substantially independent of the width of the bodyportion 14 and, in fact, the field of view, i.e., the transverse beamsweep dimension, of the swept incident beam is actually larger than thewidth of the body portion 14 at the front region 16 and at the forwardsection of the intermediate body region 20. This is, of course, enabledby the fact that the swept incident beam has been transmitted outside ofthe front and intermediate body regions of the housing. The side walls15, 17 are not in the light path and do not clip or block the sweptincident beam. The scan window 50 is mounted on the rear region 18 at anelevation above the top wall 11 to permit an overhead unobstructedtransmission.

In a preferred embodiment, the reference plane is located about 2 inchesfrom the front wall 19 of the head, and is located a linear distance ofabout 91/2 inches from the positive lens 30.

The depth of field at the reference plane is about 2 3/4" on either sideof the reference plane. These numerical figures are not intended to beself-limiting, but are merely exemplary.

A light-transmissive non-scan window 52 is mounted on the front wall 19in close adjacent confronting relationship with the sensor means 54located at the front region 16. The sensor means 54 is operative fordetecting the intensity of the light in the reflected beam coming fromthe symbol over a field of view across the same, and for generating anelectric analog signal indicative of the detected light intensity. Inorder to increase the zone of coverage of the sensor means, a pair ofsensor elements or photodiodes 54a, 54b are located on opposite sides ofthe longitudinal axis. The sensor elements lie in intersecting planesand face both forwardly and laterally. The front wall 19 is likewiseconstituted of a pair of tapered wall portions 19a, 29b each of whichhas an opening 53a, 53b formed therein. A pair of non-scan windowportions 52a, 52b is fixedly mounted behind the openings 52a, 52b,respectively. Each non-scan window portion is mounted in close adjacentconfronting relationship with its respective sensor element. Thenon-scan window portions are configured and positioned in the light pathof the reflected beam to permit the latter to pass therethrough to thesensor elements. Two small non-scan window portions are preferablyutilized, rather than a single non-scan window, because two smallerwindows are inherently stronger than one due to the greater perimeterthat two windows provide.

The scan window 50 is located rearwardly of the non-scan window 52. Eachwindow 50, 52 is located at a different distance from the referenceplane and the front wall 19. The scan window 50 is elevated above thenon-scan window 53 as described above. The non-scan window portions arelocated at opposite sides of the longitudinal axis. The scan window islocated on the longitudinal axis.

A printed circuit board 59 is mounted within the body portion 14, andvarious electrical sub-circuits diagrammatically represented byreference numerals 55, 56, 57, 58 are provided on the board 59. Signalprocessing means 55 is operative to process the analog signal generatedby the sensor to a digitized signal to generate therefrom datadescriptive of the bar code symbol. Suitable signal processing means forthis purpose was described in U.S. Pat. No. 4,251,798. Sub-circuit 56constitutes drive circuitry for the scanner motor 46. Suitable motordrive circuitry for this purpose was also described in U.S. Pat. No.4,387,297. Sub-circuits 57 and 58 constitute a safety circuit for thelaser tube, and voltage regulator circuitry. Suitable circuitry for thispurpose was also described in U.S. Pat. No. 4,387,297.

Shock mounting means are mounted at the front and rear regions of thebody portion, for shock mounting the laser, optical and scanningcomponents within the body portion. An annular shock collar 60preferably of rubber material, surrounds the forward end of the tube 22and engages the bottom wall 13 and the underside of the circuit board59. Board support elements 61a, 61b, extend downwardly of the top wall11 to rigidly support the circuit board 59. A pair of rubber shockmounts 62, 64 are fixedly mounted on opposite sides of the optical bench24, and respectively engage the side walls 15, 17 at the rear region 18of the housing. The shock mounts 62, 64 and the collar 60 are spacedlongitudinally apart of each other and engage the thin-walled housing atthree spaced locations to isolate twisting of the housing from thelaser, optical and scanning components.

Electrical power is supplied to the laser tube 22 and the deactivationmodule 100 by the power supply component 40 mounted within the handleportion 12. The power supply component which steps up a 12 DC batteryvoltage to over 1 kilovolt is the heaviest component in the head, andits mounting in the handle portion allows for a low center of gravityand for better balance of the head. In the embodiment in which asemiconductor laser is used, such a massive power supply component wouldnot be necessary.

A non-bulky, collapsible, coil-type cable 66 (see FIG. 5) electricallyconnects the head 10 to the remainder of the scanning system, whichincludes a battery-powered decode module 68 and a host computer 70. Thecoil-type cable 66 is readily flexible and permits user manipulation ofthe head 10 with multiple freedoms of movement from one symbol to thenext without requiring excessive strength by the user. The cable 66includes a plurality of conductive wires which are all relatively thinand flexible. For example, one wire carries the 12 v DC low voltagesignal from the battery in the decode module 68 to the power component40. Another wire carries the digitized signal from the analog-to-digitalsignal processing circuitry 55 to the decode module 68 for decodingpurposes. This latter wire is non-radio-frequency-shielded, and hence isreadily flexible. The remaining wires carry low voltage control andcommunication signals. All of the wires of the cable 66 are connectedtogether to a common plug-type connector 72. A mating connector 74 ismounted within the head and receives the connector 72 in a matingrelationship. The use of the mating connectors 72, 74 permits rapidreplacement of the cable for onsite repairs. The electrical connectionsbetween the connector 74 and the various components in the head havebeen omitted from the drawing for the sake of clarity.

As shown in FIG. 5, the decode module 68 processes the digitized signalgenerated in the head, and calculates the desired data, e.g., themultiple digit representation or code of the bar code symbol, inaccordance with an algorithm contained in a software program. The decodemodule 68 includes a PROM for holding the control program, a RAM fortemporary data storage, and a microprocessor which controls the PROM andRAM and does the desired calculations. The decode module also includescontrol circuitry for controlling the actuatable components in the headas described below, as well as two-way communications circuitry forcommunication with the head and/or with the host computer 70. The hostcomputer 70 is essentially a large database, and provides informationfor the decoded symbol. For example, the host computer can provideretail price information corresponding to the decoded symbols.

A manually-actuatable trigger switch 76 is mounted on the head in theregion where the handle portion 12 is joined to the body portion 14.Depression of the trigger switch 76 is operative to turn themicroprocessor in the decode module on. Upon release of the triggerswitch, the spring 78 restores the switch to its initial position, andthe microprocessor is turned off. In turn, the microprocessor iselectrically connected to the actuatable components in the head via thecable 66 to actuate and deactuate the actuatable components when themicroprocessor is respectively turned on or off by the trigger switch.

The trigger switch turns the microprocessor on or off and, may also beused to turn all of the actuatable components in the head on or off,including the deactivating module 100. Thus, deactivation of the tag insuch an embodiment may be achieved by depressing the trigger. Themicroprocessor is a large power drain on the battery built in the decodemodule. Hence, by controlling the on-time of the microprocessor to onlythose times when a symbol is being read, that is, when the triggerswitch is depressed, the power drain is substantially reduced, and thebattery life substantially increased (over 5 hours).

Another feature of one embodiment of this invention is embodied inturning the microprocessor on or off by means of the host computer 70which is remote from the head 10. The computer 70 typically includes akeyboard and a display. Once a user makes an entry on the keyboard, forexample, by entering the identity of the code to be decoded, thecomputer requests the microprocessor to turn itself on, to store theinformation, and then to turn the microprocessor off. Themicroprocessor, again, is only on for so long as is necessary to complywith the computer request. The trigger switch and the keyboard computerentry are independently operable means for directly controlling theactuatable components in the head.

Another useful feature in having the microprocessor, rather than thetrigger switch, directly control the light source is, in the case of alaser, to keep an measurement record of laser on-time in order to complywith regulatory requirements. It is, of course, far easier to keep trackof laser on-time in the software of a microprocessor than to manuallyrecord the laser on-time.

A set of visual indicators or lamps 80, 82, 84 is also mounted on thecircuit board 59, each lamp being positioned below a correspondingopening in the top wall 11. The lamps are operative to visually indicateto the user the status of the scanning system. For example, lamp 80illuminates whenever the laser tube is energized, thereby continuouslyadvising the user whether the tube is on or off. Lamp 82 illuminateswhen a successful decode has been obtained. It will be recalled that theincident beam is swept over a symbol at a rate of about 40 scans persecond. The reflected beam may be successfully decoded on the firstscan, or on any of the successive scans. Whenever a successful scan hasbeen obtained, the microprocessor will cause the lamp 82 to beilluminated to advise the user that the head is ready to read anothersymbol. Lamp 84 may be illuminated when a successful tag deactivationhas occurred, such as indicated by a return signal from the tag.

It is believed that the operation of the scanning system is self-evidentfrom the foregoing, but by way of brief review, the gun-shaped head isgrasped by its handle portion, and its barrel is aimed at the bar codesymbol to be read. The pointing of the barrel in the general directionof the symbol is facilitated by the fact that the barrel isnarrow-bodied, and that there are no obstructions on the front andintermediate body regions of the barrel. The front wall of the barrel istypically situated close to the symbol, it being understood that thesymbol can be located anywhere in the depth of field at either side ofthe reference plane.

The trigger switch is then depressed, thereby causing the microprocessorto energize the laser tube or light source, the scanner motor, thesensor elements, and all the electronic circuitry provided on theprinted circuit board. The light source emits a beam which is thenrouted through the optic train as described above, and thereupon, thescanning mirror reflects the beam through the scan window and out of thehead exteriorly of and past the front and intermediate body regions ofthe body portion of the head. The reflected beam passes through thenon-scan window portions to the sensor elements and is subsequentlyprocessed by the signal processing circuitry. The processed signal isconducted to the decode module for decoding. Once a successful decodehas been realized, the microprocessor illuminates the lamp 82. If thetrigger switch is pulled to its second position, a deactivation signalwill be generated. Once the tag has been deactivated, the lamp 84 willilluminate. The user is now advised that the head is ready to be aimedat another symbol. The flexibility of the coil-type cable facilitatesthe movement of the head to the next symbol.

In addition, the movement of the head from one symbol to the next isfacilitated by the relatively low weight of the head. The head with allthe aforementioned components therein weighs less than one pound.

FIG. 6 illustrates another embodiment of the present invention in apoint-of-sale terminal that includes a table-top directional opticalscanner for multidirectionally scanning a light-reflecting target, suchas an article including a bar code symbol on the surface. The articlesare placed on a table-top within the field of view of a detector and amultidirectional scan pattern is generated that permits the scanner toread the randomly-oriented bar code symbols.

The figure shows a point-of-sale terminal 111 including a card reader112, a keyboard 113, and display 114. A scanner including a base 115 anda scanning head 116 is coupled to the terminal 111 and functions to readbar code symbols on articles placed on field of view plane 117. A creditcard or "smart card" 110 may also be used in connection with theterminal 111 so that the customer's purchases as read by the scanninghead 116 may be automatically paid for by the customer through use of acredit card or cash card. The system further includes a deactivationunit 118 which is coupled to the base 115 of the scanning head 116.

There are a number of possible scanning modes that we are considering inconnection with stand mounted laser scanners: (a) the normal triggeredmode; (b) the triggered spot and scan mode; and (c) the dual positiontrigger mode according to the present invention.

In the normal triggered mode, the laser beam is normally off. An "objectscanner" is used in the normal triggered mode with a stand mountedscanner to detect the presence of an object in the field of view of thescanner and to initiate the rapid and repetitive scanning of the targetsymbol. For proper counting, it is necessary to distinguish between thesituation in which many scans have been performed on a single object, orthe situation in which one or more scans have been performed on aplurality of objects with identical symbols. The capability of sensingeach object to be scanned in its turn is critical for successfulapplications of bar code scanning in data collection, inventory, and thelike.

As is known in prior art hand held scanners (such as described in U.S.Pat. No. 4,387,297), a trigger or its equivalent is operative foractuating the scanning means to repetitively sweep the bar code symbol anumber of times each time the trigger is actuated. In a hand-held unit,the trigger is preferably a manually-depressible switch mounted on thehousing in the vicinity of the interconnection of the barrel and handleportions of the housing. The trigger switch is located on the handleportion such that the forefinger of the user's hand can be used tomanually depress the switch. Each time the switch is depressed thescanner sweeps the symbol many times, until a complete decode or a timeout is reached. In a stand mounted unit, a two position switch (notshown) could be used. A key on the keyboard 113 could perform the samefunction, but we will use the single term "switch" for simplicity.

The first position of the switch corresponds to the function ofinitiating the scanning and the second position corresponds to thefunction of deactivating the surveillance tag. The user has the optionof scanning alone, or deactivating the tag alone by moving the switch toposition number 1 or position number 2 respectively. An alternate use ofsuch a two position switch by a user would be to first initiatescanning, and after it has been determined that a successful decode hastaken place (by a audible beep), the user can initiate deactivation bymoving the switch to the second position. Successful deactivation may beindicated by an audible beep of a different tone.

In the triggered mode, when the decode circuitry successfully decodesthe symbol, the decode circuitry generates a successful decode signaland may actuate the indicator located in the scanner. The indicator maybe an auditory-type beeper and/or a light emitting diode. When thebeeper sounds and/or when the diode lights up, then the user knows thatthe scanning for that particular symbol has been terminated.

In the triggered spot and scan mode, as described in U.S. Pat. No.4,933,538, after the object sensor determines the presence of an object,the beam comes on at a narrow angle. In such an operational mode, a verybright, short line about 1 inch in length is formed by the laser narrowscanning beam. The bright small line is used by the user to move thelabel under the line so that the bar code may be read. When an indiciapattern indicative of a bar code symbol has been detected, the beam willwiden thereby sweeping the entire symbol so that it can be decoded.

In the dual position spot and scan mode, according to the presentinvention, after the object sensor detects the presence of an object andis set to a first position, the beam is directed in a fixed,non-scanning path. In such an operational mode, a very bright spot about240 microns in diameter (at about 31/2 inches from nose) is formed bythe laser narrow scanning beam. The bright spot is used by the userholding the laser scanner to manually aim and direct the beam to thelocation where the user actually sees the bar code is located. Typicallythe user will position the spot approximately at the center of the barcode. The user will then activate the switch to a second position toinitiate scanning. When the second position of the switch is reached,the beam will widen to sweep the entire symbol so that it can bedecoded. Although in some cases the beam may be dimly reflective or notvisible to the user, since the beam has already been positioned, thesweep will cover the symbol and decode will take place.

Although the embodiment shown in FIG. 6 is a table-top typescanning/deactivation unit, it may also be implemented in the form of amobile shopping cart. In such embodiment, which is not shown in thedrawing, the customer would wheel the cart through a merchandise,inventory, or material area. Upon selecting specific merchandise, thecustomer would scan the label, thereby deactivating it and meanwhilekeeping a running tally of the amount charged.

As an example, consider the following technique. To charge an article tobe purchased, a patron inserts his credit card into the reader 112 to beautomatically read and verified against a data base containing thenumber of all valid account numbers. If the credit card number is notfound in the file, the transaction will not proceed and the alphanumericdisplay unit 114 advises the user to consult with an authorized person.In the case of a mobile shopping cart embodiment, deactivation will notoccur and the customer is prevented from removing merchandise. In any ofthese cases, a switch may be employed so that an authorized person hasthe capability to override the transaction if desired.

It will be understood that each of the elements described above, or twoor more together, also may find useful application in other types ofconstructions differing from the types described above.

In all of the various embodiments, the elements of the scanner may beassembled into a very compact package that allows the scanner to befabricated as a single printed circuit board or integral module. Such amodule can interchangeably be used as the laser scanning element for avariety of different types of data acquisition systems. For example, themodule may be alternately used in a hand-held scanner, a table topscanner attached to a flexible arm or mounting extending over thesurface of the table or attached to the underside of the table top, ormounted as a subcomponent or subassembly of a more sophisticated dataacquisition system.

The module would advantageously comprise a laser/optics subassemblymounted on a support, a scanning element such as a rotating orreciprocating mirror, and a photodetector component. Control or datalines associated with such components may be connected to an electricalconnector mounted on the edge or external surface of the module toenable the module to be electrically connected to a mating connectorassociated with other elements of the data-acquisition system.

An individual module may have specific scanning characteristicsassociated with it, e.g. operability at a certain working distance, oroperability with a certain density of symbols. The scanningcharacteristics may also be defined through the manual setting ofcontrol switches associated with the module. The user may also adapt thedata acquisition system to scan different types of articles or thesystem may be adapted for different applications by interchangingmodules on the data acquisition system through the use of the simpleelectrical connector.

The scanning module described above may also be implemented within aself-contained data acquisition system including one or more suchcomponents as keyboard, display, data storage application software, anddata bases. Such a system may also include a communications interface topermit the data acquisition system to communicate with other componentsof a local area network or with the telephone exchange network, eitherthrough a modem or an ISDN interface, or by low power radio broadcastfrom the portable terminal to a stationary receiver.

FIG. 7A illustrates another table-top, point-of-transaction system forprocessing articles bearing light-reflective, coded indicia identifyingthe articles. For example, a garment 120 bears a hang tag 122 on which asymbol 124 is printed.

Removably attached to the garment 120 is a surveillance tag 126 alsobearing a light-reflective, coded indicium, such as a symbol 128thereon. The symbol 128 identifies the tag and is preferably printed onthe tag itself, or on a label permanently adhered to the tag. Thesymbols 124, 128 may be identical or different and, if different, may besequentially numbered.

As best shown in FIG. 8A, the tag 126 includes a pin member 130, asocket member 134 for receiving the pin member 130, and a plasticsupport 136 in which the socket member 134 is embedded and on which thesymbol 128 (or a label bearing the symbol 128) is carried. The members130, 134 are separable, typically by a magnetic decoupler 166 known, perse, in the art.

The FIG. 7A system includes a self-checkout terminal 140 supported on acountertop or like supporting surface 142. The terminal 140 includes anoverhead housing 144, a base 146, and an upright 148 for supporting thehousing 144 above the base 146. The base has an upper work surface 150on and over which the symbols 124, 128 are successively passedunderneath the housing 144.

As shown diagrammatically in FIG. 8A, the housing 144 has a laser source152 for emitting a light beam, an optical train 154 for opticallymodifying and focusing the beam to a reading spot located in thevicinity of the work surface 150, a scanner 156 for scanning the lightbeam in a scan pattern over the work surface, an exit port 158 throughwhich the beam passes exteriorly of the housing en route to the worksurface, a detector 160 for detecting scattered light reflected off thesymbol 124 or 128, a digitizer 162 for converting an electrical analogsignal indicative of the detected light intensity of the scattered lightto a digitized signal, and a control microprocessor 164 operative fordecoding the digitized signal in accordance with a stored algorithm intodata representative of the article or the tag. The controlmicroprocessor 164 operatively connects to the decoupler 166 andselectively enables and disables the operation of the decoupler 166.

The base 146 contains the conventional decoupler 166 which isoperatively connected to a well 168 extending into the work surface 150.A credit card reader 170, also known, per se, is also contained in thebase 146 and is operatively connected to a slot 172 in which a creditcard or analogous payment card 174 is inserted. The card typicallysupports a strip of magnetically-encoded data.

A manual entry keyboard 176 having numerical and function keys isprovided on the base, together with a display 178 for displayinginformation and, as described below, for displaying prompting messagesto a user. A speaker 180 may also be used for broadcasting auditoryprompting messages.

A flow-chart illustrating a specific embodiment of the operation of aself-checkout system, in which only those surveillance tags attached toarticles which have been purchased are permitted to be removed, is shownin FIG. 9A. For this embodiment, the symbol 128 on each surveillance tag126 is formed on an attachable label and is selected to be the same asthe symbol 124 on the corresponding hanger tag 122. A device isdisclosed in U.S. Pat. No. 4,746,932, which is herein incorporated byreference, which allows a user to read a symbol (i.e., the symbol 124 onthe hanger tag 122) and then prints on an attachable label a symbolidentical to the symbol read. This attachable label, having symbol 128printed thereon, is then attached to the surveillance tag 126.

Referring to FIG. 9A, at STEP 182, the message "PRESENT ARTICLE LABEL"is displayed on the display 178 so that a customer, upon approaching theterminal 140, will know that the terminal is available for use.

At STEP 183, when the customer passes the hanger tag 122 between theupper work surface 150 and the housing 144, the symbol 124 is read anddecoded in the well known manner, and the decoded value thereof isstored in the microprocessor 164.

At STEP 184, the microprocessor uses the decoded value of the symbol 124obtained in. STEP 183 to interrogate a description and price database(not shown) to obtain the description and the price of the article 120to which the hanger tag 122 is attached. The article description andprice are displayed on the display 178.

At STEP 185, the message "Do YOU WANT TO PURCHASE THIS ARTICLE?" isplaced on the display 178. If the user responds YES, by pressing apredetermined key on the keyboard 176, progress is made to STEP 186,where the decoded value of the symbol 124 is stored in memory (notshown) within the microprocessor 164 and the price of the article isadded to a Running Total Price for this checkout sequence. The RunningTotal Price is displayed 178 so that the customer can see the total costof all articles purchases. However, if the customer responds No at STEP185, by pressing a predetermined key, progress is made to STEP 187.

At STEP 187, the message "MORE ARTICLE TO BE PURCHASED?" appears on thedisplay 178. If the user responds YES, by pressing a predetermined keyon the keyboard 176, the flow branches back to STEP 182 where the nextarticle can be processed. If the customer responds NO, by pressing apredetermined key, progress is made to STEP 188 where the customer isinstructed by the display 178 to "ENTER CREDIT CARD". When thecustomer's credit card 174 is entered into slot 172 the credit cardreader 170 is activated.

At STEP 188 the credit card transaction for the Running Total Price iseffected in the normal way. For example, the terminal 146 maycommunicate with a remote facility where the transaction is approved.

At STEP 190, if the credit card transaction is denied, an appropriatemessage is displayed to the customer apprising them of the denial anddirecting them not to remove the articles from the store. Since thesurveillance tags 126 are still attached to the articles 120, attemptsto remove the articles 120 from the store would be detected in thenormal manner. If the credit card transaction is approved, progress ismade to STEP 191.

At STEP 191, the display prompts the customer to present thesurveillance tag 126 for removal by displaying the message "PRESENT TAGFOR REMOVAL".

AT STEP 192, the customer presents the surveillance tag 126 for removalby positioning the tag in a deactivation region (i.e., by inserting thepin member 130 of the tag into the well 168). The microcomputer detectsthe insertion of the pin member 130 by detection means (not shown), suchas, for example, an optical switch, mechanical switch, hall effectswitch, etc. Responsive to such detection, the microcomputer 164activates the reader within the housing 144 to automatically read thesymbol 128 on the surveillance tag 126. Alternative, the detection meanscan be eliminated and the customer can be required to press apredetermined key on the keypad 176 after the insertion of the pinmember 130 into the well 168 is completed. Responsive to thepredetermined key the microcomputer activates the reader. At step 193,the symbol 128 read in step 192 is compared with the symbols 124 of thehanger tags 122 previously stored in memory at STEP 186, and if a matchis found, it is determined that the surveillance tag 126 is attached toan article 120 which has been properly purchased, and therefore, can beremove from the article. If no match is found, the article 120 has notbeen purchased, and therefore, the tag should not be removed andprogress is made to STEP 191.

At STEP 194, the microcomputer 164 enables the decoupler 166 which inturn removes, or permits the customer to remove, the pin 130. Further,the microcomputer removes from memory one copy of the symbol 128 of theremoved surveillance tag 126 so as to prevent a similar surveillance tag126, attached to a similar article, from being removed. In this manner,only tags associated with articles which have been purchased can beremoved from the articles.

At STEP 195, the microcomputer checks the memory to determine whetherthere are still symbols 124, which were stored in STEP 186, containedtherein. If YES, progress is made to STEP 191 where more surveillancetags 126 can be removed.

At STEP 196, the surveillance tags 126 of all the article which werepurchased have been removed. The customer is instructed "CHECKOUTCOMPLETE, REMOVE YOUR CREDIT CARD".

As can be appreciated, in the system described in FIG. 9A, only thosesurveillance tags 126 attached to articles which have been purchased arepermitted to be removed in STEPS 191-195. Accordingly, a customer who isusing the self-checkout counter is prevented from removing surveillancetags. 126 from articles other than those articles purchased. Forexample, if the customer purchases in STEPS 182-190 an article costing$20 (i.e., a shirt), the customer is prevented in STEPS 191-195 frompurposely, or inadvertently, removing a surveillance tag from a moreexpensive article (i.e., a fur coat), which has not been purchase. Ascan be appreciated, a self-checkout counter, as described, can beoperated by a customer as opposed to a store employee, thereby reducingthe staffing requirements, while at the same time assuring that theft orinadvertent removal of articles which have not been purchased isprevented.

In the embodiment described with reference to FIG. 9A, the symbol 124 onthe hanger tag 122 and the symbol 128 on each corresponding surveillancetag 126 are identical. However, in a further embodiment, eachsurveillance tag 126 is provided with an unique symbol 128 (i.e., whenthe surveillance tags 126 are manufactured an unique symbol 128 isprinted on each). In this embodiment, after the hanger tag 122 and thesurveillance tag 126 are attached to an article, the symbol 124 on eachhanger tag 122, and the symbol 128 on each corresponding surveillancetag 126 are read and associated with each other, with such associationbeing stored in a database (Conversion Database) (not shown) which canbe accessed by the microcomputer 164.

In this embodiment,, STEPS 182-192 and 194-196, as shown in FIG. 9,remain the same. However, STEP 193 is modified as follows.

At STEP 193, the symbol 128 read in STEP 192 is used by themicrocomputer 164 to extract from the conversion database (not shown)the symbol which has been associated therewith. If the symbol 128 is notfound in the conversion database, it is determined that this particularsurveillance tag 126 should not be removed and progress is made to STEP191. If an associated symbol is found in the conversion database, thisassociated symbol is compared with the symbols 124 of the hanger tags122 previously stored in memory at STEP 186, and if a match is found, itis determined that the surveillance tag 126 is attached to an article120 which has been properly purchased, and therefore, can be remove fromthe article. If no match is found, the article 120 has not beenpurchased, and therefore, the tag should not be removed and progress ismade to STEP 191.

A still further embodiment is describe with reference to the flow chartof FIG. 10A. In this embodiment, the hanger tags 122 are not required.The symbol 128 on the surveillance tag 126 is used to particularlyidentify each article 120. For example, the symbol 128, which identifieseach article 120, is printed on a label which is then affixed to thesurveillance tag 126.

Referring to FIG. 10A, at STEP 197, the message "PRESENT TAG" isdisplayed on the display 178 so that a customer, upon approaching theterminal 140, will know that the terminal is available for self-checkoutoperation.

At STEP 198, when the customer passes the surveillance tag 126 betweenthe upper work surface 150 and the housing 144, the symbol 128 is readand decoded in the well known manner, and the decoded value thereof isstored in the microprocessor 164.

At STEP 199, the microprocessor uses the decoded value of the symbol 128obtained in STEP 198 to interrogate a description and price database(not shown) to obtain the description and the price of the article 120to which the surveillance tag 126 is attached. The article descriptionand price are displayed on the display 178.

At STEP 200, the message "DO YOU WANT TO PURCHASE THIS ARTICLE?" isplaced on the display 178. If the user responds YES, by pressing apredetermined key on the keyboard 176, progress is made to STEP 201,where the decoded value of the symbol 128 is stored in memory (notshown) within the microprocessor 164 and the price of the article isadded to a Running Total Price for this checkout sequence. The RunningTotal Price is displayed 178 so that the customer can see the total costof all articles purchases. However, if the customer responds NO at STEP200, by pressing a predetermined key, progress is made to STEP 202.

At STEP 202, the message "MORE ARTICLE TO BE PURCHASED?" appears on thedisplay 178. If the user responds YES, by pressing a predetermined keyon the keyboard 176, the flow branches back to STEP 197 where the nextarticle can be processed. If the customer responds NO, by pressing apredetermined key, progress is made to STEP 203 where the customer isinstructed by the display 178 to "ENTER CREDIT CARD". When thecustomer's credit card 174 is entered into slot 172 the credit cardreader 170 is activated.

At STEP 203 the customer is instructed by the display 178 to "ENTERCREDIT CARD".

At STEP 204 the credit card transaction for the Running Total Price iseffected in the normal way. For example, the terminal 146 maycommunicate with a remote facility where the transaction is approved.

At STEP 205, if the credit card transaction is denied, an appropriatemessage is displayed to the customer apprising them of the denial anddirecting them not to remove the articles from the store. Since thesurveillance tags 126 are still attached to the articles 120, attemptsto remove the articles 120 from the store would be detected in thenormal manner. If the credit card transaction is approved, progress ismade to STEP 206.

At STEP 206, the display prompts the customer to present thesurveillance tag 126 for removal by displaying the message "PRESENT TAGFOR REMOVAL".

AT STEP 207, the customer presents the surveillance tag 126 for removalby positioning the tag in a deactivation region (i.e., by inserting thepin member 130 of the tag 126 into the well 168). The microcomputerdetects the insertion of the pin member 130 by detection means (notshown), such as, for example, an optical switch, mechanical switch, halleffect switch, etc. Responsive to such detection, the microcomputer 164activates the reader within the housing 144 to automatically read thesymbol 128 on the surveillance tag 126. Alternatively, the detectionmeans can be eliminated and the customer can be required to press apredetermined key on the keypad 176 after the insertion of the pinmember 130 into the well 168 is completed. Responsive to thepredetermined key the microcomputer activates the reader.

At STEP 208, the symbol 128 read in step 192 is compared with thesymbols 128 of the surveillance tags 126 previously stored in memory atSTEP 201, and if a match is found, it is determined that thesurveillance tag 126 is attached to an article 120 which has beenproperly purchased, and therefore, can be remove from the article. If nomatch is found, the article 120 has not been purchased, and therefore,the tag should not be removed and progress is made to STEP 206.

At STEP 209, the microcomputer 164 enables the decoupler 166 which inturn removes, or permits the customer to remove, the pin 130. Further,the microcomputer removes from memory one copy of the symbol 128 of theremoved surveillance tag 126 so as to prevent a similar surveillance tag126, attached to a similar article, from being removed. In this manner,only tags associated with articles which have been purchased can beremoved from the articles.

At STEP 210, the microcomputer checks the memory to determine whetherthere are still symbols 128, which were stored in STEP 201, containedtherein. If YES, progress is made to STEP 206 where more surveillancetags 126 can be removed.

At STEP 211, the surveillance tags 126 of all the article which werepurchased have been removed. The customer is instructed "CHECKOUTCOMPLETE, REMOVE YOUR CREDIT CARD".

As can be appreciated, the embodiment described with reference to FIG.10A provides for a reliable and secure self-checkout operation, wherethe customer is prevented from purposely or inadvertently removingsurveillance tags from articles which have not been purchased. Further,in this embodiment, the requirement of attaching both an attached hangertag 122 and a surveillance tag 126 to each article 120 is eliminated.

In the embodiments described with reference to FIG. 9A, each article isscanned and selected for purchase (STEPS 182-187), then the credit cardtransaction is processed (STEPS 203-205), followed by the process ofremoving all the appropriate surveillance tags 126 (STEPS 191-195).Accordingly, each article is required to be handled twice by thecustomer (i.e., first to scan and purchase the article and then, afterthe credit card transaction, the article is handled a second time toeffect removal of the surveillance tag 126).

A still further embodiment is described with reference to FIG. 11,where, in effecting self-checkout, the customer only has to pick up eacharticle 120 a single time. For this embodiment, the symbol 124 of thehanger tag 122 is the same value as the symbol 128 on the correspondingsurveillance tag 126. Referring to the flow chart of FIG. 11, at STEP212, the display 178 instructs the customer to enter their credit card174 (or a debit card such as "smart card") into slot 172.

At STEP 213, the card reader 170 reads the card 174 and, in a mannerwell known in the art, determines the amount of credit available forthat card. For example, where the card 174 is a credit card, the cardreader 170 communicates with a remote facility (not shown) whichprovides information regarding the available credit on the card 174. Inthe case where the card 174 is a debit card ("smart card"), the cardreader 170 can read the contents of the debit card 174 to determine theavailable credit.

At STEP 214, the message "PRESENT ARTICLE LABEL" is displayed on thedisplay 178

At STEP 215, when the customer passes the hanger tag 122 between theupper work surface 150 and the housing 144, the symbol 124 is read anddecoded in the well known manner, and the decoded value thereof isstored in the microprocessor 164.

At STEP 216, the microprocessor uses the decoded value of the symbol 124obtained in STEP 183 to interrogate a description and price database(not shown) to obtain the description and the price of the article 120to which the hanger tag 122 is attached. The article description andprice are displayed on the display 178.

At STEP 217, the price for the article 120 is compared with the totalcredit determined to be available for card 174 in STEP 213. If thearticle's price is greater than the credit available for the card 174,progress is made to STEP 218 where the message "INSUFFICIENT FUNDS, YOURAVAILABLE CREDIT IS $₋₋ " is placed on the display 178. If sufficientcredit is available, progress is made to STEP 219.

At STEP 219, the message "DO YOU WANT TO PURCHASE THIS ARTICLE?" isplaced on the display 178. If the user responds YES by pressing apredetermined key on the keyboard 176, progress is made to STEP 220.However, if the customer responds NO by pressing a predetermined key,progress is made to STEP 225.

At STEP 220, the display prompts the customer to present thesurveillance tag 126 for removal by displaying the message "PRESENT TAGFOR REMOVAL".

AT STEP 221, the customer presents the surveillance tag 126 for removalby placing the tag 126 in a deactivation region (i.e., by inserting thepin member 130 of the tag 126 into the well 168). The microcomputerdetects the insertion of the pin member 130 by detection means (notshown), such as, for example, an optical switch, mechanical switch, halleffect switch, etc. Responsive to such detection, the microcomputer 164activates the reader within the housing 144 to automatically read thesymbol 128 on the surveillance tag 126. Alternative, the detection meanscan be eliminated and the customer can be required to press apredetermined key on the keypad 176 after the insertion of the pinmember 130 into the well 168 is completed. Responsive to thepredetermined key the microcomputer activates the reader.

At STEP 222, the symbol 124 read in step 215 is compared with the symbol128 of the surveillance tag 126 read in STEP 221, and if they match, itis determined that the surveillance tag 126 is attached to an article120 which has been selected for purchase, and therefore, can be removefrom the article. If no match is found, the article 120 has not beenselected for purchase, and therefore, the tag should not be removed andprogress is made to STEP 220.

At STEP 223, the microcomputer 164 enables the decoupler 166 which inturn removes, or permits the customer to remove, the pin 130.

At STEP 224, the microcomputer instructs the card reader to debit thecard 174 by the amount of the purchase price for the article 120. Themicrocomputer also adds the price of the article to a running totalprice which is then displayed on the display 178.

At STEP 225, the message "MORE ARTICLE TO BE PURCHASED?" appears on thedisplay 178. If the user responds YES, by pressing a predetermined keyon the keyboard 176, the flow branches back to STEP 213 where the nextarticle can be processed. If the customer responds NO, by pressing apredetermined key, progress is made to STEP 226 where the message"CHECKOUT COMPLETED, REMOVE YOUR CREDIT CARD" is displayed 178.

As can be appreciated, in the embodiment describe with reference to FIG.11, after the customer inserts their credit card 174 into the slot (STEP212), the customer is only required to handle each article 120 once toeffect the purchase and the removal of the surveillance tag 126. Moreparticularly, the customer will pick-up an article 120 to be purchasedand in STEPS 214-219 the article will be selected for purchase. Then,without being required to place the article down, STEPS 220-223 areeffected to remove the surveillance tag 126.

In a still further embodiment, a system for, and method of, confirmingwhen a surveillance tag 126 is removed from an article 120 is describedwith the aid of FIG. 12A. STEPS 182-191 and STEPS 195-196 of FIG. 12 areidentical to the corresponding STEPS described previously with referenceto FIG. 9A, and therefore, repeated description thereof is omitted.

In STEP 227, when the tag is presented for removal by placing the tag inthe deactivation region (i.e., by inserting the pin member 130 into thewell 168), the decoupler 166 separates the pin member 130 from thesocket member 134. Concomitantly, with the separation of the pin member130 and the socket member 134, the microprocessor 164 activates thereader within the housing 144 to automatically read the symbol 128. Themicroprocessor then stores in memory information that the tag 126 havingthe symbol 128 has been removed.

Accordingly, in this embodiment, the use of the coded symbol on thesurveillance tag insures that the system is reliably and automaticallyadvised when tag removal has occurred.

The foregoing aspects of the inventions have been illustrated anddescribed as functioning with non-deactivatable surveillance tags 126which are mechanically locked to the articles 120, and where the tags126 are removed to allow removal of the article. However, it is notintended that the invention be so limited, since various types ofdeactivatable type tags can be used in accordance with the presentinvention, where the deactivatable type tag is deactivated instead ofbeing removed from the article. For example, referring to STEP 194 ofFIG. 9A, instead of removing the tag 126 using a decoupler, adeactivatable type tag placed in the deactivating region can bedeactivated by, for example, inductively coupling an electromagneticfield to the tag. As a further alternative, as means for acceptingpayment, the credit card reader 170 can be replaced by a cash reader(i.e., cash is received, evaluated and stored). Still further, theoverhead scanner 156 can be replaced with slot scanner for reading barcodes.

In particular, FIGS. 7b through 12b illustrate an alternative embodimentof the present invention which is identical to that shown in FIGS. 7athrough 12a except the tag removal apparatus and method steps arereplaced with tag deactivation apparatus and method steps. Thosecomponents and steps in FIGS. 7b-12b identical to those in FIGS. 7a-12aare given the same reference numerals. The embodiments shown in FIGS.7b-12b operate in the same fashion as those corresponding embodiments inFIGS. 7a-12a except for the tag which is initially in the activatedstate, is deactivated by a tag deactivation means 166a rather thanremoved when a match is found between the symbol 124 of the hanger tag122 and the symbol 128 of the surveillance tag 126.

While the foregoing aspects of the invention have been illustrated anddescribed as embodied in a self-checkout, point-of-transaction systemincluding removable, electro-optically coded surveillance tags, it isnot intended to be limited to the details shown, since variousmodifications and structural changes may be made without departing inany way from the spirit of the present invention.

A further aspect of the present invention is shown in FIG. 13. Thesymbol 128 (i.e., coded indicia) on the surveillance tag 126 is visuallydisplayed on a liquid crystal display 240 (LCD) included in the tag 126.The contrast between the ON and the OFF segments 241 of the LCD issufficient to enable the symbol 128 displayed on the LCD to be read anddecoded by conventional scanner means. The use of an LCD in asurveillance tag for displaying alphanumeric characters representing theprice and description of an article to which the tag is attached isdescribed in U.S. Pat. No. 5,005,125. However, it is noted that U.S.Pat. No. 5,005,125 does not use the LCD to display machine readablesymbols (for example, bar codes) as now described.

U.S. Pat. No. 5,003,251, which is hereby incorporated by reference, isdirected to mounting an LCD to a printed circuit board, where the LCDdisplays bar codes which uniquely identifies the board. When the boardundergoes testing and evaluation, the results are stored in computermemory along with the identification number. Subsequent to the time oftesting, if anyone is interested in reviewing the original test data,the bar code displayed on the LCD is scanned which indirectly addressesthe data.

The LCD 240 has a number of uniform rectangularly shaped segments 241arranged in a parallel relationship. Each segment can be selectivelyturned ON (i.e., appears black) or turned OFF (i.e., appears white) bythe LCD driver means 242. In this way the symbol 128 displayed on theLCD can be dynamically changed. A microcomputer 243 contains an internalmemory (not shown), which stores a string of ASCII characterscorresponding to the symbol 128 to be displayed on the LCD. Receivingmeans 244 receives and decodes control signals and provides the decodedcontrol signal to the microcomputer 243. The microcomputer 243 changesthe contents of the internal memory (not shown) based on the contents ofthe decoded control signal.

The receiving means 244 can be, for example, a RF transceiver forcommunicating with remote RF devices. U.S. Pat. No. 5,029,183, hereinincorporated by reference, describes a RF communication network andprotocol for RF communications. Further, the receiving means 244 can bea light sensing device which is responsive to the laser light of ascanner which is normally used to scan the symbol. To communicate withthe receiving means 244, the scanner is arranged to modulate its laserto communicate to the receiver means information relating to the symbolto be displayed. The receiving means 244 demodulates the received signaland provides the demodulated signal to the microcomputer 243. Stillfurther, the receiving means 244 can be circuitry arranged to receivedata from keyboards, remote computers, remote scanning terminals, remoteinfrared LED's, etc.

The microcomputer 243 determines, based on the ASCII value for thesymbol stored in the internal memory (not shown), which of the segments241 are required to be ON and which are required to be OFF in accordancewith the bar code symbology selected for the particular tag 126, andcommunicates such information to the LCD driving means 242. The LCDdriving means 242 then causes the segments 241 on the LCD 240 to displaythe bar code symbol 128 which corresponds to the ASCII value stored inthe internal memory.

The symbol 128 displayed on the LCD 240 of the tag 126 described in FIG.13 can be dynamically altered based upon the data provided by thereceiving means 244. In this way, the symbol 128 for the tag 126 can beinitially set, and subsequently changed, without requiring that thesymbol be printed on a label to be affixed to the tag, or that thesymbol be printed directly on the tag.

A further use for the dynamically alterable symbol, is described withreference to FIG. 7. The symbol 124 on the hanger tag 122 can be scannedby a portable scanning terminal (not shown). The portable scanningterminal then communicates the decoded value of the symbol 124 to thereceiving means 244 of the surveillance tag 126, which then displays onthe LCD 240 a symbol 128 which corresponds to the symbol 124 on thehanger tag. In this way, the symbol 128 on the surveillance tag 126 isset to match the symbol 124 on the hanger tag 122. Still further, any ofthe embodiments previously described with reference to FIGS. 9-12 canutilize a tag 126 having a dynamically alterable symbol 128 as describedwith reference to FIG. 13.

The surveillance tag 126 as shown in FIG. 13, which has a dynamicallyalterable symbol 128, can also be used effectively in pricemarkdown/markup applications. In price markdown/markup application, atleast a portion of the symbol 128 on the surveillance tag 126 is used torepresent, in machine readable form, the price of the attached article.To effect a price change, an updated symbol, including therein a newprice, is provided to the receiving means 244 of the tag 126, andtherefore, the symbol 128 on the tag is changed to reflect the newprice.

The price markdown/markup application above described providesadditional labor savings when the receiving means 244 of the tag 126 isa transceiver which is arranged to receive RF communications from aremote RF transmitter (not shown). Accordingly, the remote RFtransmitter is used to transmit the new price information to eachsurveillance tag 126 which requires the price change. In this way, theprice changes are effected remotely without requiring a person tophysically visit each surveillance tag to effect the change.

As further aspects of the present invention, LCD displays can be used indevices other than surveillance tags for dynamically displaying machinereadable symbols. For example, referring to FIG. 14, a gas meter 250 isshown where preprinted (not dynamic) symbols 251 are combined withdynamically alterable symbols 241 displayed on an LCD display. In theembodiment shown, the preprinted symbols 251 contain predeterminedinformation associated with a person responsible for paying for the gasusage. A gas flow measuring device 252 measures the volume of gas usedand periodically communicates the results through the receiving means244 to the microprocessor 243. The receiving means 244, themicroprocessor 243, the LCD driver 242 and the LCD 240 are the same asthose described in FIG. 13. Accordingly, responsive to the signalreceived by the receiving means, the tag 126 displays on the LCD 240 asymbol which corresponds to the volume of gas used.

When reading the meter, both the preprinted symbols 251 and the dynamicsymbol 241, representative of the gas usage, can be read and decodeusing a portable scanning terminal (for example, Symbol Technologiesmodel LRT3800) and the results stored in a database. The database canthen be downloaded to a computer which prepares bills. As can beappreciated, since both the preprinted symbols 251 and the dynamicsymbol 241 are automatically read by the portable scanning terminal, thereliability of the data is much higher than if some of the informationwas manually entered.

While the above aspects of the present invention have been illustratedand described as embodied in a surveillance tag, shelf tag and in a gasmeter, it is not intended that the dynamically alterable symbol to belimited to the details and applications shown, since variations andmodifications and structural changes can be made without departing inany way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can readily adapt it for variousapplications without omitting features that, from the standpoint ofprior art, fairly constitute essential characteristics of the generic orspecific aspects of this invention and, therefore, such adaptationsshould and are intended to be comprehended within the meaning and rangeof equivalence of the following claims.

What is claimed as new and desired to be protected by letters patent isset forth in the appended claims:
 1. A point of-transaction system forprocessing articles having attached surveillance tags, each surveillancetag having an activated state and a deactivated state, each of thesurveillance tags bearing coded indicia and being initially in anactivated state, the point-of-transaction system defining a deactivatedregion in space in which only one of the surveillance tags at a giventime may be positioned in order to change the surveillance tag from anactivated state into a deactivated state, the system comprising:a) aplurality of surveillance tags, each surveillance tag being attached toone of a plurality of articles available for purchase, each tag bearingcoded indicia; b) a deactivator for deactivating a selected one of theplurality surveillance tags positioned in the deactivation region; c) areader for electro-optically reading the indicia on the selected one ofthe plurality of tags while the tag is positioned in the deactivationregion and when a reader activation signal is obtained; and d) acontroller for detecting when the deactivator deactivates the selectedone of the plurality of tags and for forming a reader activation signal.2. An apparatus for processing an article having an attachedsurveillance tag, where the surveillance tag bears a light-reflectivecoded indicia, comprising:a) a deactivator for deactivating thesurveillance tag; b) an activatable reader for electro-optically readingthe indicia on the surveillance tag; and c) a controller for detectingwhen the deactivator deactivates the surveillance tag and for activatingthe reader to read the indicia on the surveillance tag.
 3. A method ofconfirming deactivation of a surveillance tag which is attached to anarticle, the surveillance tag having an activated state and adeactivated state, the surveillance tag initially having an activatedstate which can be changed to the deactivated state when thesurveillance tag is placed in a deactivation region, the surveillancetag bearing a coded indicia, the method comprising the steps of:a)positioning the surveillance tag in the deactivation region; b) changingthe state of the surveillance tag positioned in the deactivation regionfrom the activated state to the deactivated state; c) detecting when thesurveillance tag positioned in the deactivation region is changed fromthe activated state to the deactivated state and forming a positivedeactivation signal; and d) reading electro-optically the indicia on thesurveillance tag positioned in the deactivation region, said readingbeing responsive to the positive deactivation signal.